The age variable in the data of Exercise 10.42 was collapsed to only two levels as shown...

The age variable in the data of Exercise 10.42 was collapsed to only two levels as shown here:

The results from Minitab are shown here:

a. Is there significant evidence of an association between age and promotion decision?

b. What is the impact of combining the age categories? Compare the answers obtained here to the answers from Exercise 10.42

REFERENCE:

10.42 : A study of potential age discrimination considers promotions among middle managers in a large company. The data are as follows:

Output from Minitab software is given here:

a. Find the expected numbers in each cell under the hypothesis of independence of age and promotion.

b. Justify the indicated degrees of freedom.

c. Is there significant evidence of a relation between age and promotion?